Kolkata:The family of the college student, who was killed and chopped into pieces for allegedly protesting anti-social activities in West Bengal's North 24 Parganas district, on Sunday demanded a CBI probe into his death, as thousands turned out to pay their last respects to the slain youth.

Police arrested one person in connection with the murder case, but the prime suspect remained untraced. The flower-bedecked body of Sourav Chowdhury was driven in a hearse to his locality in Bamangachi, as nearly 6,000 mourners came out of their houses and crowded around the vehicle. Many offered flowers. The distraught parents of the deceased - weeping inconsolably and in a daze - had their last glimpse of their boy.

Later, the body was taken to the crematorium, as youths of the area took out a candle light vigil on the route. Of the four people named in the first information report, one has been nabbed. A district court later remanded him in police custody for seven days. However, prime suspect Shyamal Karmakar continues to be missing along with two others, police said.

The body of Sourav - missing since Friday night - was found beside the railway track between Duttapukur and Bamangachi stations on Saturday. His family and local residents alleged he was murdered for protesting criminal activities in the Bamangachi area. The body parts were discovered lying scattered along the tracks. Sandip Chowdhury, elder brother of Sourav, said: "Both of us used to protest against anti-social activities. So they (the goons) wanted to kill either of us. The miscreants were earlier sheltered by the CPI-M (Communist Party of India-Marxist), and now by the ruling Trinamool Congress."

Alleging that efforts were afoot to hush up the issue, Sandip said he did not have confidence in the administration. "I will go to the Central Bureau of Investigation. If it fails, then I'll approach the Supreme Court." He said he did not have any confidence in Chief Minister Mamata Banerjee, "as we are not getting any help from the administration". Sourav's post-mortem examination was conducted in the city's Nil Ratan Sarkar Medical College and Hospital during the day.

Protests continued in Bamangachi for the second day. Shops and markets remained closed following a 12-hour shutdown called by the Bharatiya Janata Party and the Socialist Unity Centre of India-Communist. Irate locals also ransacked the house of a relative of prime suspect Karmakar. Political leaders, rights organisations and some eminent persons visited the area and called on the victim's family members.

State BJP president Rahul Sinha, who consoled Sourav's grieving parents, alleged that police were working at the promptings of an invisible authority. "I think there is a conspiracy behind this incident. At various stages of the conspiracy one can see the hand of the Trinamool Congress. The family has demanded a CBI probe. I think a CBI inquiry is indeed needed," he said.

Condemning the murder, Left Front chairman Biman Bose alleged that efforts were on to dilute the crime's gravity by raking up a debate on his political affiliation. "He had to pay with his life for protesting against the anti-social activities in the area. We don't have words to condemn the barbaric incident. "At the same time we also condemn the way attempts are being made to dilute the gravity of the incident by raking up a debate over his political affiliation," Bose told media persons here.

"We urge people cutting across the political spectrum to raise their voice against the murder. We demand exemplary punishment of the culprits," he said. A team of rights group Association for Protection of Democratic Rights and a delegation comprising professors, teachers and the father of Barun Biswas - an anti-rape protestor who was killed two years back - also visited the bereaved family.